feat: disable client statistics (#23371) (#23378)

Disable the client side statistics
collection and sending when
it is disabled for the server.

part of #23357

Co-authored-by: caalador <mikael.grankvist@vaadin.com>

Author: vaadin-bot

flow-server/src/main/java/com/vaadin/flow/server/communication/IndexHtmlRequestHandler.java

@@ -449,6 +449,8 @@ private void addDevTools(Document indexDocument,
         if (isAllowedDevToolsHost(config, request)) {
             devToolsConf.put("token", DevToolsToken.getToken());
         }
+        devToolsConf.put("usageStatisticsEnabled",
+                config.isUsageStatisticsEnabled());
         addScript(indexDocument, String.format("""
                 window.Vaadin.devToolsPlugins = [];
                 window.Vaadin.devToolsConf = %s;

vaadin-dev-server/src/main/frontend/vaadin-dev-tools.ts

@@ -81,6 +81,7 @@ type DevToolsConf = {
   backend?: string;
   liveReloadPort?: number;
   token?: string;
+  usageStatisticsEnabled?: boolean;
 };
 
 // @ts-ignore
@@ -709,6 +710,13 @@ export class VaadinDevTools extends LitElement {
       if (!VaadinDevTools.isActive) {
         frontendConnection.setActive(false);
       }
+      if (this.conf.usageStatisticsEnabled === false) {
+        localStorage.setItem('vaadin.statistics.optout', 'true');
+        localStorage.removeItem('vaadin.statistics.basket');
+        localStorage.removeItem('vaadin.statistics.firstuse');
+      } else {
+        localStorage.removeItem('vaadin.statistics.optout');
+      }
       this.elementTelemetry();
     };
     frontendConnection.onConnectionError = onConnectionError;